Radioreceiver



March 4, 1930.

W. KITTO RADIORECEIVER Filed June 10. 1925 2 Sheets-Sheet l ation/wijd March 4, 1930. w H, Km0 l 1,749,102

RADIORECEIVER I Filed June l0. 1925 2 Sheets-Sheet 2 www v l gwoentoz PatentedMarrdp i* i l n A' l lSTIAIEs'. PATENT OFFICE wiimtriiirrY 'HENRYu Krrfro, or rERNnALE, MICHIGAN y y nienroniicmvnn Application meaiune 1o, 1925.` serial No. 36,125.

This invention relates to radio circuits or three element vacuum tube to connect the hookups employing vacuum tubes, wherein grid of the stabilizing tube to the grid of the considerable trouble is often experienced in tube being stabilized, and to connect the plate preventing the oscillation of such tubes which of the stabilizing tube with the positive B- 1 5 is ka frequent source of trouble in many types battery line. l 50 ofjhoolups,especially 'cascaded radio frc- Still further objects subsidiary to or refquency circuits, greatly interferring with sulting from the aforesaid objects or from tuning' and reception and otherwise adding the construction or operation of the inven- K dificulties hto the vproper operation of the tion as it maybe carried into effect, will be- 1510 receiver. l 'f f f come apparent as the said invention is here- 5 As the circumstances under which such os,- inafter further disclosed.

cillati'onf occurs'is generally appreciated by In carrying the said invention into effect, thoseversed in the art to'whichfthis invention I v,may provide in a radio frequency circuit appertains, althoughthe Vfundamental reahaving,`say, two stagesof radio frequency l sonsrfor'theA phenomena may be in some reamplification arranged in cascade formation G0 spects` obscure, as is the casewith .most elecwherein one of the lament leads ofthe radio l trica'l' phenomena', particularv relation; of the frequency tubes are each connected tonthe `OIldli'iOIIS resulting in Oscillation is IlOdWelt positive A-battery supply 'and the other fila- Von extensively herein. ment leadsto the negative A-battery supply 20' The `object of the invention'is to secure in 'throughca'rheostau a stabilizing tube having 65 Y. aj 'simple' andi effective manner the stabilizra filament' shunted acrossthe leads of the i ngfof radioffreqlleIICyGlljCuits' sotliat the filament of the first radio frequency tube .l tendencyof thetubes t0 osclllate may bc H1111- with'a variable resistance interposed between 1 fimized andfeSly brought yUndef A"3OI1C101; that lead which is not connected to the A- y theinvention further contemplating thc? battery supply and the said stabilizing tube, 7o

, EIOUCOI 0f `3,I1QVB1 method 0f Controlling the adjustable contact of saidf'variable reth? PQlaltY, 0f* the' filament lead Connected sistancebeing the means establishing connecratssaiiar sitsniraiaf on v1-5e Sg ff esavizinvuean' esairs ratio yy man? Slflbleclftoy Qsfuatlon for the PWPOSJ'S frequency tubbebeing connected together and 75 heHtte-Ct f 'th-invention iS td the 'plate of the said stabilizing tube being l I' include iii such'lay circuit 'a lam or vacuum Connected t9 th? plftlve Bbattery Supply' l Y p. All of which is more particularly described tube, the filament ofsald-tube'being sliunted d rta'nd hereinafter b Wa of 6 Y across the filament of theradio frequency an las? Y. Ue l f f t ,di y y o* tube,r` the'oscillation' of 'which it isdesire'd mp amg@ Y? @rence O- e accompanymb to control, aY resistance being incorporated rvmg vlv .(rell-t h t. uw d. between the filaments ofthe said two lamps lgure l @im es SC ema 11% y l@ la 10 or! tubes and a variable Contact @tabu-Sb 1ffrrquellcy clrcuit embodying tie saic inven.. v40 ing communication-'between the said resist-` .1 Y g 'I 85 f `ance and a rheostat'controllingthe filament 'Flgufe 2 luust'ltes amoded form 0f the current of the radio frequency tube or tubes Sam?? f f u Aemployed inthe circuit. y Y Flgure 3 1s a .fragmentary view of the dia- L' V'llieinv'entionffurther aims, where'the adgram,l"i.gure 1,1llustrat1ngasomewhat modi- 41:5V ditional stabilizing/'tube is inthe form of a fied wiring ofthe stabilizing tube circuit; 90

that shown in F igure4, embodyingsiX-element tubes.

Figure 4 illustratesv a "further ,modiiied` form of hookup, and` Y YFigure 5 illustrates a similar hookup to Similar characters similar parts in the. several iigures of the drawings. v

l 1n the arrangement shown in Figure 1, thel principles ofthis invention are applied-in a` very simple and effective manner, which has proved itself veryeflicient in actual practice in a circuit having k,two stages of radio irequency amplification arranged in cascade. I

lnthisicase 1 indicates the first radio frequency amplifying tube, andv 2 a second tube,

3 being the detector tube of the circuit, VFollowing a common practice in circuits suclias that shown, the grid 4 of the tube 1 ischnected by the grid lead fthro-ughan in iuctance coil 8 and grid return 5a with lthe negative terminal 6.of the filament 7 of the said tube,.and the plate 9 ofthesaid tube is connected with 1the primary 10 of airinuctance 11 of the positive B-bat'tery supply 12. Thepositive A-batterysupply 13-is cennected to thepositive filament termin'al'14of the said tube 1. 15 is arheostat controlling the amount of current passed' through the lilaments of the tubes land 2.l So far there is nothing unusual about the circuitdescribed.V Oscillation-,of the tubes insuch radio frequency circuitsfis often diiiicultjef control, especially when two or more stages of radio frequency amplification are employed, and I propose to'minimize and control such oscillation by the incorporation in the circuitiof ay stabilizing tube 16, which may be simply a vacuum tube similar in all respects to the tube 1, and connect the negative terminal 17 of the filament 18 of this stabilizing tube with the negativev terminal 6 ofthe filament 7 through the medium ,of` a stabilizing rheostat A 19 which includes an adjustable contact119a connected tothe out-put end of the said rheo-l stat 15. The ends of theresistanceV of the saidstabilizing rheostat` are numbered21 and 22 for the sake of easier identification in the description following.

' tube is connected to thepositivej iebz'ittery` supplyl so that the iilamentof the'stabiliz;

The positive terminal 2O of the "stabilizing ing'tub'e may be said tov be shuiited across the leads ofthe yfilament of'therad'io `frequencytermediate position,ofthe said conta'ctbothv the filaments of thetube 1 and the stabilizing',

of reference indicate tube ofpositive 'polarity due to the inter-v tube 16 will burn with equal brilliancyof Y Y intensity governed A,by the iilamentrheostat 15, which may be regulated to suitthe best Y i `receiving conditions. However, if the said l Contact 19 beY moved to the vend 21 ofthe re- 76 1 sistance ofthe stabilizing rheostat 19, the filament of the stabilizing tube 16 Will -be cold, or approximately cold.y Hence, with this setting, the 'grid returnat the terminal 6 Y will beof negative polarity and of its greatest negative potential permitted by the setting of the filament rheostat 15,'and the lead con- 'i nectedto the terminal 17 'off the stabilizing position vof the resistancewof the rheostat y19 between it and the negative lcurrent ,supply from the said lilament rheostat 15.

Should the radio frequency tubes tend to yoscillatein an vundesirable manner, they may be readilystabilized by reducing the negative polarity of the grid returnwhichl is accom- .soifV plished by moving the Contact 19a of the rheo+v y 'K stat 1,9 toward the Aend 22 thereof,'vwhich reduces the'temperatureof the Vfilament 7 at the same time raising the tempera-ture ofthe lament 18l of thestabilizing tube, and ifthe rheostat be ofisufiicient resistancey and fthe adjustable contact be moved-to the said end 22thereof, the said filament 18of; the stabil y9.5

lizing tube would burn at the full briliancy permittedbythe rheostat 1-5, and the filament 7 would .become practically coldwhere upon-the gridl return will be ofjpositivepoe larity and the lead connected tothe terminal 17 of the stabilizing tubelof. negative polarrheostat ,191 is now interposed between: the' Y negative current supply yand theaterminal 6- ofthe filament 7k "i i f Itgwillbeobvious that the-negative kor posi- 100.y ity, dueto the factthat theresistanceof the i f ltivepotential at the said terminal 6 will there-i L y fore'bevariedrelatively,'or reversed, accord'- ing to the adjustment ofthe contact19aandf it will also be apparentthatfthe rheostat -15 controls the volume of current supplied v'to both theamplifying tube andthe stabilizing' tube, no additional current is consumed by Y the application of the rstabilizing tube tothe circuit inthe manner described. f

i The'stabilizing tube may beone, which has lost its usefulness other than that: the lament has not been burned out, in whichcase only the filament may be employed*inthe-circuit .as hereinbeforeset forth, vbut where the tube is f still capable y*of .operation as an` amplifier or rectifier, I prefer' toco'uple the g'ridl 23 thereofto the grid 4 of the amplifying tube 1 and to connect 'the plate 24 of the'stabilizing tube withthe'B-battery supply 121asishown in said Figure-1., whereby the said'stabilizing tube tends to also impress a -stabilizingcurrent in the primary 10 ofy the induceV tance 11.

If the rheostat 15 in Figurel is turned *Y up or adjusted to ka point-which raises l.the

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gether they emit, electrons at as great or a slightly greater rate than the plate potential can attract them through the anodes 24 and 9,

.the plate current flow between the said anodes yandthesaid filaments is limited to a specific amount, and if the filament 7 israised to a A higher temperature than 18, by` adjusting arm n 19? toward `21,"then"the plate4 current flow will"be"greaterfrom the anode9 to filamenti' than fromk anode 24 to filament 18, and therefore more vB current will flow from line 12 through coil to anode 9 thanfrom line 12 n to anode 24. yInversely andwith the rheostat 15 still inthe same position, if the temperature of filament 18 lis yraised andthat of filament 7 lowered by adjustment of arm '19,

{,thenthe platey current flow willbe greater Vfrom anode 24 to filament 18 than that from' Y through coil .10, thus controlling lthe strength of the oscillations through coil 10.

The arrangement shown in Figure 2is sim--4 ',ilar in all respects, except that anincandesp fcent lamp 25 has yits lfilament 26 shunted .f across'the grid return 5a and the A-battery )supply in place of the vacuum tube 16 shown in the first figure, the said incandescent lamp being of practically the same amperage as y i the amplifying tube 1, and the operation inv controlling the polarity of the current re-v Vturn is effected in the manner already described. Y

' Y In Figure 3 thearrangement shown in Figi ure 1 is 'simply modified bythe connectingA of the grid returnf yof the secondary coil 11i l i of the inductance 11 by a wire 27 to the negative terminal 6 of the first amplifying tube,V

so that the vpolarity of the saidl grid return V.4,0 isalso varied and inthe same manner as the polarity ofthe grid return 6. This arrangement is preferred where more thank two stages of radio frequency amplification are employed, although it isl also'very successyfully applicable f where ,there are yonly two `stages of radio frequency amplification.

yGO

The said arrangement, Figure 3, also differs fr'om'Figurel in'that the plate 24 of the stabilizingy tube is connected to thejsame end ofthe primary 10 as the plate 9 of the first amplifying tube-1.1 This operates to assist *Y inthe impressing of weak signals on the said n primary 10` and requires a greater movement of the Contact 19 to effect stabilizing, but for general purposes'of reception the arrangevmentgof the plate leads as shownin Figure 1 is preferred.

' In.. :Figure 4, the secondl amplifying tube 2' is indicatedas being individually providedV A, `rwith' a" furtherstabilizing tube 28 associated n therewith in the same manner as the stabilizing tube kof the firstamplifying tube, 29 be'- ing anfadditional'stabilizing rheostat, 30 the ing and'mplifying tubes of the second stage respectively. f i

#In 'Figure 5 thecircuit is identical with Figurev4 4, except that separate amplifying tubes vare not used but six-element vacuum tubes34xandy 35 employed for both the first and Vsecond stages of radio frequency amplification, the filaments 36y and 37 ofthe tube l34rserving in the same manner as the filaments 7 and'18'of the tubes 1 and 16, and the filaments 38 and 39 serving as the filaments 33 and 32 of the tubes 2 and 28 of the second stage shown in Figure 4.

` The inclusion of a stabilizing tube or tubes in a radio frequency circuit along the lines suggested herein greatly facilitates proper operation of a radio receiver both as to stabilizing of the operation of the amplifying tubes and control of volume, so that signals of greatly varying intensity may be reproducedy with a minimum of distortion and freedom from extraneous noises due to improperly stabilized radio frequency amplify-v ing tubes. o Due to the great number and variety of circuits to which such an arrangement is applicable and the many types of tubes and lamps'available for employment, the invention' admits of being carried into effect in many ways without departing from the essential yfeatures thereof, and it is, therefore, desired that the specification be read as being merely illustrative and not in a limiting sense, except as necessitated by the prior art.

' vWhat I claim is n 1. In a radio circuit having more than one stage of amplification including an amplifying tube, an output inductance in its circuit,

the plate of the amplifying tube of one of said stages being connected with its output inductance, stabilizing meanscomprising a stabilizingtube similar to said amplifying tube having its filaments shunted across the yfilament leads of said amplifying tube, means for variably changing and reversing the potential and polarity of the filaments of said amplifying and stabilizing tubes relative to one another, the grids of said tubes being coupled together and having a common return to the filament of said amplifying tube, and the plate of said stabilizing tube being connected to said inductance.

2. rIn a circuit comprising an input inductance, an output transformer and an amplifying tube, an' additional tube having a filament shunted across the filament leads of said amplifying tube, a rheostat interposed between the negative leads of said tubes, a movable contact cooperating with said rheostat, a source of A current supply, said Contact being connected to the'negative terminal of said source, the grids of each tube being connected to one end of said input in- 2ln i 157495-102 cluctanc'e, theother end of said input inductance being Connected tothe negative leadof said first named amplifying tube, the plate` of said amplifying tube being connected to one end of the primarywinding of said out-V put transformer, al source'of B current sup- Y l ply, the other end of said output transformer being *connected*V to the plate of said aflditional tube and'to the positive terminal of said source offB current supply.

Intestimony whereof I afiiX my signature.Y y

WILLIAMv HENRY- KIT-TO; 

